| 1. |
|
|
| 2. |
- Bergmann, Peter, et al.
(författare)
-
Combination of seismic reflection and constrained resistivity inversion with an application to 4D imaging of the CO2 storage site, Ketzin, Germany
- 2014
-
Ingår i: Geophysics. - : Society of Exploration Geophysicists. - 0016-8033 .- 1942-2156. ; 79:2, s. B37-B50
-
Tidskriftsartikel (refereegranskat)abstract
- A combination of seismic and geoelectric processing was studied by means of a structurally constrained inversion approach. Structural constraints were interpreted from the seismic data and integrated into the geoelectric inversion through a local regularization, which allowed inverted resistivities to behave discontinuously across defined boundaries. This arranged seismic processing and constrained resistivity inversion in a sequential workflow, making the generic assumption that the petrophysical parameters of both methods change across common lithostructural boundaries. We evaluated the approach using a numerical example and a real data example from the Ketzin CO2 pilot storage site, Germany. The latter demonstrated the efficiency of this approach for combining 4D seismic and surface-downhole geoelectric data. In consistence with the synthetic example, the constrained resistivity inversions produced clearer delineated images along the boundary between caprock and reservoir formation. Near the CO2-flooded reservoir, the seismic and geoelectric time-lapse anomalies correlated well. At some distance to the downhole electrodes, however, the geoelectric images conveyed a notably lower resolution in comparison to the corresponding seismic images. Both methods confirm a northwesterly trend for the CO2 migration at the Ketzin site, although a rather northerly direction was initially expected. The results demonstrate the relevance of the presented approach for the combination of both methods for integrated geophysical CO2 storage monitoring.
|
|
| 3. |
|
|
| 4. |
- Bergmann, Peter, et al.
(författare)
-
Review on geophysical monitoring of CO2 injection at Ketzin, Germany
- 2016
-
Ingår i: Journal of Petroleum Science and Engineering. - : Elsevier BV. - 0920-4105. ; 139, s. 112-136
-
Tidskriftsartikel (refereegranskat)abstract
- Geophysical monitoring activities were an important component of the CO2 injection program at the Ketzin site, Germany. Here we report on the seismic and electrical resistivity tomography (ERT) measurements performed during the period of the site development and CO2 injection. Details on the site geology, the history of the CO2 injection operation, and petrophysical models relevant for the interpretation of the geophysical data are presented. The seismic measurements comprise 2D and 3D surface seismic surveys, vertical seismic profilings, and crosshole measurements. Apart from the measurements, results from advanced processing methods, such as impedance inversion and full-waveform inversion are also presented. In addition, results from crosshole ERT and surface-downhole ERT are presented. If operational efforts are taken into consideration we conclude that a combination of several geophysical methods is preferable given the demands of a spatiotemporally comprehensive monitoring program. We base this conclusion on that the different imaging characteristics and petrophysical sensitivities of different methods can complement each other. An important finding is, based on signal quality and reduced operational costs, that the use of permanent installations is promising. Generally, specific monitoring layouts will depend on site-specific characteristics, such as reservoir depth, availability of wells, petrophysical characteristics, and accessibility of surface locations. Given the comprehensive range of methods applied, the reported results are not only relevant to the operation of CO2 storage sites, but are also of interest to other monitoring projects dealing with fluid injection or production.
|
|
| 5. |
|
|
| 6. |
- Bergmann, Peter, et al.
(författare)
-
Time-lapse difference static correction using prestack crosscorrelations : 4D seismic image enhancement case from Ketzin
- 2014
-
Ingår i: Geophysics. - : Society of Exploration Geophysicists. - 0016-8033 .- 1942-2156. ; 79:6, s. B243-B252
-
Tidskriftsartikel (refereegranskat)abstract
- A method for static correction of time-lapse differences in reflection arrival times of time-lapse prestack seismic data is presented. These arrival-time differences are typically caused by changes in the near-surface velocities between the acquisitions and had a detrimental impact on time-lapse seismic imaging. Trace-to-trace time shifts of the data sets from different vintages are determined by crosscorrelations. The time shifts are decomposed in a surface-consistent manner, which yields static corrections that tie the repeat data to the baseline data. Hence, this approach implies that new refraction static corrections for the repeat data sets are unnecessary. The approach is demonstrated on a 4D seismic data set from the Ketzin CO2 pilot storage site, Germany, and is compared with the result of an initial processing that was based on separate refraction static corrections. It is shown that the time-lapse difference static correction approach reduces 4D noise more effectively than separate refraction static corrections and is significantly less labor intensive.
|
|
| 7. |
- DeFelipe, Irene, et al.
(författare)
-
Reassessing the lithosphere : SeisDARE, an open-access seismic data repository
- 2021
-
Ingår i: Earth System Science Data. - : Copernicus Publications. - 1866-3508 .- 1866-3516. ; 13:3, s. 1053-1071
-
Tidskriftsartikel (refereegranskat)abstract
- Seismic reflection data (normal incidence and wide angle) are unique assets for solid Earth sciences as they provide critical information about the physical properties and structure of the lithosphere as well as about the shallow subsurface for exploration purposes. The resolution of these seismic data is highly appreciated; however they are logistically complex and expensive to acquire, and their geographical coverage is limited. Therefore, it is essential to make the most of the data that have already been acquired. The collation and dissemination of seismic open-access data are then key to promote accurate and innovative research and to enhance new interpretations of legacy data. This work presents the Seismic DAta REpository (SeisDARE), which is, to our knowledge, one of the first comprehensive open-access online databases that stores seismic data registered with a permanent identifier (DOI). The datasets included here are openly accessible online and guarantee the FAIR (findable, accessible, interoperable, reusable) principles of data management, granting the inclusion of each dataset in a statistics referencing database so its impact can be measured. SeisDARE includes seismic data acquired in the last 4 decades in the Iberian Peninsula and Morocco. These areas have attracted the attention of international researchers in the fields of geology and geophysics due to the exceptional outcrops of the Variscan and Alpine orogens and wide foreland basins, the crustal structure of the offshore margins that resulted from a complex plate kinematic evolution, and the vast quantities of natural resources contained within. This database has been built thanks to a network of national and international institutions, promoting a multidisciplinary research and is open for international data exchange and collaborations. As part of this international collaboration, and as a model for inclusion of other global seismic datasets, SeisDARE also hosts seismic data acquired in Hardeman County, Texas (USA), within the COCORP project (Consortium for Continental Reflection Profiling). SeisDARE aims to make easily accessible old and recently acquired seismic data and to establish a framework for future seismic data management plans. SeisDARE is freely available at https://digital.csic.es/handle/10261/101879 (a detailed list of the datasets can be found in Table 1), bringing endless research and teaching opportunities to the scientific, industrial, and educational communities.
|
|
| 8. |
- Fei, Huang, 1987-, et al.
(författare)
-
DMO processing on the Ketzin 3D seismic data
- 2014
-
Konferensbidrag (refereegranskat)abstract
- The Dip-moveout (DMO) correction is a process which attempts to make the finite offset data closer to zero offset data after the normal-moveout (NMO) correction. The NMO correction is then dip independent and reflections with different dips will stack coherently. DMO plays a critical role in seismic processing by enhancing the final image quality of the seismic data. In this study, we apply 3D Squeezing DMO (Hale and Artley, 1993) to seismic data from the Ketzin pilot CO2 site after NMO to study the impact of DMO on time-lapse seismic imaging and to investigate if it enhances the CO2 seismic monitoring technique. This 3D DMO method is based on an integral approach and incorporates Hale and Artley’s (1993) modifications for variable velocity with time. A constant velocity algorithm is used with a gamma correction function which depends on the velocity function. An anti-alias velocity of 3000 m/s is used for the DMO. After DMO the data are stacked and F-XY deconvolution is applied. Finally, 3D finite-difference migration using the final smoothed NMO velocities is performed for each data set.We then apply a time-lapse analysis to the 3D seismic data sets and compare the results with and without DMO processing. The most important aspect of the DMO processing is determining the velocity field for the NMO step. This is done by using the initial smoothed velocity field obtained from the conventional velocity analysis before DMO as a first estimate. The data are input into the DMO process and then inverse NMO is applied. These data are then subjected to a new velocity analysis and the velocity field is updated and used as input for the NMO process. A number of iterations are generally required until the velocity field does not need further updating. In this study velocities were picked at every 20th CDP in the inline and crossline directions. Compared to the velocity spectrum without DMO processing, the velocity trend is improved and the ambiguity in the velocity picks is eliminated after DMO correction. The improved accuracy of velocity picking makes it easier to interpret the velocity spectrum and obtain correct interval velocities. Considering the stacked section, DMO suppresses the random noise to a greater extent and thus the signal-to-noise ratio is enhanced. From the comparison of the amplitude difference horizon at the reservoir level, the shape of the anomaly observed in the data with DMO processing is similar to that observed in the data without DMO processing. However, the amplitude anomalies of the former are stronger than those of the latter, especially close to the injection well. In addition, one stronger amplitude anomaly in the DMO time-lapse horizon indicates a preferred trend of the CO2 migration in WNW direction due to the reservoir heterogeneity.
|
|
| 9. |
- Grevemeyer, Ingo, et al.
(författare)
-
Structure of oceanic crust and serpentinization at subduction trenches
- 2018
-
Ingår i: Geosphere. - 1553-040X. ; 14:2, s. 395-418
-
Tidskriftsartikel (refereegranskat)abstract
- The subducting oceanic lithosphere may carry a large amount of chemically bound water into the deep Earth interior, returning water to the mantle, facilitating melting, and hence keeping the mantle mobile and, in turn, nurturing plate tectonics. Bending-related faulting in the trench–outer rise region prior to subduction has been recognized to be an important process, promoting the return flux of water into the mantle. Extensional faults in the trench–outer rise are opening pathways into the lithosphere, supporting hydration of the lithosphere, including alteration of dry peridotite to water-rich serpentine. In this paper, we review and summarize recent work suggesting that bend faulting is indeed a key process in the global water cycle, albeit not yet well understood. Two features are found in a worldwide compilation of tomographic velocity models derived from wide-angle seismic data, indicating that oceanic lithosphere is strongly modified when approaching a deep-sea trench: (1) seismic velocities in both the lower crust and upper mantle are significantly reduced compared to the structure found in the vicinity of mid-ocean ridges and in mature crust away from subduction zones; and (2) profiles shot perpendicular to the trench show both crustal and upper mantle velocities decreasing systematically approaching the trench axis, highlighting an evolutionary process because velocity reduction is related to deformation, alteration, and hydration. P-wave velocity anomalies suggest that mantle serpentinization at trenches is a global feature of all subducting oceanic plates older than 10–15 Ma. Yet, the degree of serpentinization in the uppermost mantle is not firmly established, but may range from <4% to as much as 20%, assuming that velocity reduction is solely due to hydration. A case study from the Nicaraguan trench argues that the ratio between P-wave and S-wave velocity (Vp/Vs) is a key parameter in addressing the amount of hydration. In the crust, the Vp/Vs ratio increases from <1.8 away from the trench to >1.9 in the trench, supporting the development of water-filled cracks where bend faulting occurs. In the mantle, the Vp/Vs ratio increases from ∼1.75 in the outer rise to values of >1.8 at the trench, indicating the increasing intensity of serpentinization.
|
|
| 10. |
- Huang, Fei, et al.
(författare)
-
Feasibility of utilizing wavelet phase to map the CO2 plume at the Ketzin pilot site, Germany
- 2017
-
Ingår i: Geophysical Prospecting. - : Wiley. - 0016-8025 .- 1365-2478. ; 65:2, s. 523-543
-
Tidskriftsartikel (refereegranskat)abstract
- Spectral decomposition is a powerful tool that can provide geological details dependent upon discrete frequencies. Complex spectral decomposition using inversion strategies differs from conventional spectral decomposition methods in that it produces not only frequency information but also wavelet phase information. This method was applied to a time‐lapse three‐dimensional seismic dataset in order to test the feasibility of using wavelet phase changes to detect and map injected carbon dioxide within the reservoir at the Ketzin carbon dioxide storage site, Germany. Simplified zero‐offset forward modelling was used to help verify the effectiveness of this technique and to better understand the wavelet phase response from the highly heterogeneous storage reservoir and carbon dioxide plume. Ambient noise and signal‐to‐noise ratios were calculated from the raw data to determine the extracted wavelet phase. Strong noise caused by rainfall and the assumed spatial distribution of sandstone channels in the reservoir could be correlated with phase anomalies. Qualitative and quantitative results indicate that the wavelet phase extracted by the complex spectral decomposition technique has great potential as a practical and feasible tool for carbon dioxide detection at the Ketzin pilot site.
|
|
| 11. |
|
|
| 12. |
- Huang, Fei, 1987-, et al.
(författare)
-
Preliminary Seismic Time-lapse Results from the First Post-injection Survey at the Ketzin Pilot Site
- 2016
-
Konferensbidrag (refereegranskat)abstract
- Since the CO2SINK project start in April 2004, different methods involving seismics, geoelectrics andpressure-temperature monitoring have been applied at the Ketzin pilot site to map geological structuresand assess CO2 distribution and movement. One 3D baseline seismic survey prior to CO2 injection andtwo 3D repeat seismic surveys during CO2 injection have proven that the 3D time-lapse surface seismicmethod is an effective tool for providing good quality images of the CO2 plume. In the autumn of 2015, athird 3D repeat seismic survey, serving as the first post-injection survey, was acquired. The preliminaryresults show that the predominant westward trend of the CO2 migration is in agreement with the previousresults. No CO2 migration upwards through the caprock was detected. The decrease in the size of CO2plume may be related to ongoing dissolution into the saline formation water.
|
|
| 13. |
|
|
| 14. |
- Huang, Fei, 1987-, et al.
(författare)
-
The first post-injection seismic monitor survey at the Ketzin pilot CO2 storage site : results from time-lapse analysis
- 2018
-
Ingår i: Geophysical Prospecting. - : Wiley. - 0016-8025 .- 1365-2478. ; 66:1, s. 62-84
-
Tidskriftsartikel (refereegranskat)abstract
- The injection of CO2 at the Ketzin pilot CO2 storage site started in June 2008 and ended in August 2013. During the 62 months of injection, a total amount of about 67 kt of CO2 was injected into a saline aquifer. A third repeat 3D seismic survey, serving as the first post-injection survey was acquired in 2015, aiming to investigate the recent movement of the injected CO2. Consistent with the previous two time-lapse surveys, a predominantly WNW migration of the gaseous CO2 plume in the up-dip direction within the reservoir is inferred in this first post-injection survey. No systematic anomalies are detected through the reservoir overburden. The extent of the CO2 plume west of the injection site is almost identical to that found in the 2012 second repeat survey (after injection of 61 kt), however there is a significant decrease in its size east of the injection site. Assessment of the CO2 plume distribution suggests that the decrease in the size of the anomaly may be due to multiple factors, such as limited vertical resolution, CO2 dissolution and CO2 diffusion, in addition to the effects of ambient noise. 4D seismic modelling based on dynamic flow simulations indicates that a dynamic balance between the newly injected CO2 after the second repeat survey and the CO2 being dissolved and diffused was reached by the time of the first post-injection survey. Considering the considerable uncertainties in CO2 mass estimation, both patchy and non-patchy saturation models for the Ketzin site were taken into consideration.
|
|
| 15. |
|
|
| 16. |
- Ivandic, Monika, et al.
(författare)
-
Geophysical monitoring at the Ketzin pilot site for CO2 storage : New insights into the plume evolution
- 2015
-
Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836 .- 1878-0148. ; 32, s. 90-105
-
Tidskriftsartikel (refereegranskat)abstract
- To date, 3D time-lapse seismic monitoring at the Ketzin CO2 storage pilot site comprised a baseline survey conducted in 2005 and two repeat surveys conducted in 2009 and 2012. At the time of the first repeat survey (22-25 kt of CO2), the CO2 plume was found to be concentrated around the injection well with a maximum lateral extent of approximately 300-400 m and a thickness of 5-20m. Data from the 2012 survey (61 kt of CO2), show further growth and migration of the amplitude anomaly interpreted to be induced by the CO2 injection. The anomaly is similar in shape to that obtained from the 2009 survey, but significantly stronger and larger by similar to 150m in the N-S direction and by similar to 200m in the E-W direction. In agreement with the 2009 survey, the new data show a westward propagation of the plume, a trend governed by the complex structure of the reservoir. No evidence of systematic changes in the seismic signature within the overburden is observed. A quantitative assessment of the plume reveals a 15% discrepancy with the injected amount, which could be attributed to the ongoing dissolution processes. However, the estimated quantity also contains significant uncertainty.
|
|
| 17. |
|
|
| 18. |
|
|
| 19. |
|
|
| 20. |
- Ivandic, Monika, et al.
(författare)
-
Monitoring CO2 saturation using time-lapse amplitude versus offset analysis of 3D seismic data from the Ketzin CO2 storage pilot site, Germany
- 2018
-
Ingår i: Geophysical Prospecting. - : WILEY. - 0016-8025 .- 1365-2478. ; 66:8, s. 1568-1585
-
Tidskriftsartikel (refereegranskat)abstract
- The injection of CO2 at the Ketzin pilot site commenced in June 2008 and was terminated in August 2013 after 67 kT had been injected into a saline formation at a depth of 630-650 m. As part of the site monitoring program, four 3D surface seismic surveys have been acquired to date, one baseline and three repeats, of which two were conducted during the injection period, and one during the post-injection phase. The surveys have provided the most comprehensive images of the spreading CO2 plume within the reservoir layer. Both petrophysical experiments on core samples from the Ketzin reservoir and spectral decomposition of the 3D time-lapse seismic data show that the reservoir pore pressure change due to CO2 injection has a rather minor impact on the seismic amplitudes. Therefore, the observed amplitude anomaly is interpreted to be mainly due to CO2 saturation. In this study, amplitude versus offset analysis has been applied to investigate the amplitude versus offset response from the top of the sandstone reservoir during the injection and post-injection phases, and utilize it to obtain a more quantitative assessment of the CO2 gaseous saturation changes. Based on the amplitude versus offset modelling, a prominent decrease in the intercept values imaged at the top of the reservoir around the injection well is indeed associated solely with the CO2 saturation increase. Any change in the gradient values, which would, in case it was positive, be the only signature induced by the reservoir pressure variations, has not been observed. The amplitude versus offset intercept change is, therefore, entirely ascribed to CO2 saturation and used for its quantitative assessment. The estimated CO2 saturation values around the injection area in the range of 40%-60% are similar to those obtained earlier from pulsed neutron-gamma logging. The highest values of 80% are found in the second seismic repeat in close vicinity to the injection and observation wells.
|
|
| 21. |
|
|
| 22. |
|
|
| 23. |
|
|
| 24. |
- Ivandic, Monika, et al.
(författare)
-
Subsurface seismic imaging with a hammer drilling source at an exploration drilling test center in Örebro, Sweden
- 2022
-
Ingår i: Advances in Geosciences. - : European Geosciences Union (EGU). - 1680-7340 .- 1680-7359. ; 56, s. 163-169
-
Tidskriftsartikel (refereegranskat)abstract
- Seismic imaging while drilling (SWD) technology offers possibilities of imaging ahead of the drill-bit, which could be useful for determining when to go from hammer drilling to core drilling. Also, seismic images of the surrounding rock can improve geological models which could be then used to guide drilling programs.An SWD field test was carried out in August 2020 at an exploration drilling test site in Örebro, Sweden, with the aim to determine if the signals from hammer drilling can be used for seismic imaging around the drill-bit in a hard-rock environment where the strong drill-rig noise interference is one of the main challenges. The test site had previously been investigated with various geophysical methods, geological mapping and diamond core drilling, and it therefore represented an ideal location to perform this feasibility study.After data pre-processing and cross-correlation with the trace from the geophone closest to the rig, the shot-gathers were vertically stacked over the length of a drill pipe to achieve further signal improvement. A comparison with the active seismic data shows reasonable agreement, in spite of the fact that the noise level is significant even after careful processing. However, the lack of clear reflections in the active seismic data, indicating no detectable changes in the bedrock lithology in the near surface, hinders the full assessment of the seismic signal generated with hammer drilling at this site.
|
|
| 25. |
- Ivandic, Monika, et al.
(författare)
-
Subsurface seismic imaging with a hammer drilling source at an exploration drilling test center in Örebro, Sweden
- 2021
-
Ingår i: EGU General Assembly 2021. - : Copernicus GmbH.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- <p>Seismic imaging while drilling technology offers possibilities of imaging ahead of the drill-bit, which could be useful for determining when to go from hammer drilling to core drilling. Moreover, seismic images of the surrounding rock can improve geological models which could be then used to guide drilling programs.</p><p>A seismic imaging while drilling field test was carried out in August 2020 at the I-EDDA Test Center next to the Epiroc factory in &#214;rebro, which is an outcome of the EIT Raw Materials funded project &#8220;Innovative Exploration Drilling and Data Acquisition (I-EDDA)&#8221;. The purpose of the test presented here was to determine if the signals from hammer drilling can be used for seismic imaging around the drill-bit. The I-EDDA test site has been extensively investigated with geophysical investigations, geological mapping and diamond core drilling, and it therefore represents an ideal location to perform the proposed feasibility study.</p><p>The data were recorded along a west-east oriented line consisting of 45 active 1C vertical geophones with a spacing of about 2 m and the rig located approximately in the middle of the profile. A reference signal, which is usually recorded by the pilot sensor fixed to the top of the drill string to be used to convert geophone recordings to impulsive-like seismic data, was not available. The passive recordings on the surface were thus correlated with the trace from the geophone closest to the rig.</p><p>After data pre-processing and cross-correlation, the shot-gathers were vertically stacked over the length of a drill pipe to achieve further signal improvement. A comparison with the results of a modelling study shows certain agreement. However, it has to be noted that the velocity model obtained from earlier studies and used to generate the synthetic data set here is rather a simple one and the noise level in the real data set is still significant, in spite of careful processing. Besides the strong contamination by the rig noise, more typical for data with smaller offsets, the mono-frequency waveform footprints present in the cross-correlograms, which have been observed in similar experiments where a trace from the nearest geophone was used to approximate the bit signal, could also play a role. The recent results from the active seismic studies conducted at the site have not detected any clear reflections within the bedrock, which further hinders the quality assessment of the seismic signal.</p><p>&#160;</p><p>&#160;</p><p>This work was partly supported by VINNOVA with the project 2019-04832 titled Integrated Smart Test environment for the mining industry - SMIG. We gratefully acknowledge this financial support.</p>
|
|
| 26. |
- Ivandic, Monika, et al.
(författare)
-
Time-lapse analysis of sparse 3D seismic data from the CO2 storage pilot site at Ketzin, Germany
- 2012
-
Ingår i: Journal of Applied Geophysics. - : Elsevier BV. - 0926-9851 .- 1879-1859. ; 84, s. 14-28
-
Tidskriftsartikel (refereegranskat)abstract
- The Ketzin pilot site is the first European on-shore CO2 storage project site. Injection started in June 2008 and until the latest repeat survey in February 2011 around 45,000 t of CO2 had been injected into a saline aquifer at approximately 630 m depth. Seismic monitoring methods that have been applied at the Ketzin site comprise baseline and repeat observations at various scales. We present here time-lapse results from sparse 3D seismic data measurements at Ketzin, which were acquired to link downhole surveys with conventional 3D surface seismic surveys. The results are consistent with the 3D seismic time-lapse studies over the injection site and show that the sparse 3D geometry can be used to map the CO2 in the reservoir at a significantly lower effort than the conventional 3D surveying. The last repeat survey indicates preferential migration of the CO2 to the west. There are no indications of migration into the caprock on either of the repeat surveys.
|
|
| 27. |
- Ivandic, Monika, et al.
(författare)
-
Time-lapse AVO Analysis of 3D Surface Seismic Data Sets from the Ketzin CO2 Storage Pilot Site, Germany
- 2015
-
Konferensbidrag (refereegranskat)abstract
- Time–lapse 3D surface seismic monitoring at the Ketzin CO2 storage pilot site has provided time–lapse images of the spreading plume, which has been interpreted as being caused by fluid saturation changes only. The integration of seismic AVO/AVA modeling and petrophysical experiments on core samples from the Ketzin reservoir support the interpretation of the field data by demonstrating that pressure has a rather minor impact on the seismic amplitudes at the Ketzin site. In this study Amplitude Variation with Offset (AVO) analysis has been applied to the baseline and the latest 3D repeat data set to investigate the real AVO response from the top of the sandstone reservoir after the injection of ~ 61 kT of CO2. The results show a good agreement with the modeling results, indicating that CO2 saturation effect dominates the time–lapse seismic signature.
|
|
| 28. |
|
|
| 29. |
|
|
| 30. |
|
|
| 31. |
- Ivanova, Alexandra, et al.
(författare)
-
Monitoring and volumetric estimation of injected CO2 using 4D seismic, petrophysical data, core measurements and well logging : a case study at Ketzin, Germany
- 2012
-
Ingår i: Geophysical Prospecting. - : Wiley. - 0016-8025 .- 1365-2478. ; 60:5, s. 957-973
-
Tidskriftsartikel (refereegranskat)abstract
- More than 50 000 tons of CO2 have been injected at Ketzin into the Stuttgart Formation, a saline aquifer, at approximately 620 m depth, as of summer 2011. We present here results from the 1st repeat 3D seismic survey that was performed at the site in autumn 2009, after about 22 000 tons of CO2 had been injected. We show here that rather complex time-lapse signatures of this CO2 can be clearly observed within a radius of about 300 m from the injection well. The highly irregular amplitude response within this radius is attributed to the heterogeneity of the injection reservoir. Time delays to a reflection below the injection level are also observed. Petrophysical measurements on core samples and geophysical logging of CO2 saturation levels allow an estimate of the total amount of CO2 visible in the seismic data to be made. These estimates are somewhat lower than the actual amount of CO2 injected at the time of the survey and they are dependent upon the choice of a number of parameters. In spite of some uncertainty, the close agreement between the amount injected and the amount observed is encouraging for quantitative monitoring of a CO2 storage site using seismic methods.
|
|
| 32. |
- Joodaki, Saba, et al.
(författare)
-
Simulation of CO2 injection into a Baltic Sea saline aquifer and seismic monitoring of the plume
- 2013
-
Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; , s. 355-364
-
Tidskriftsartikel (refereegranskat)abstract
- TOUGH2/ECO2N was used to simulate CO2 injection into a saline aquifer in the Baltic Sea and the effect of different amounts of CO2 injection on the seismic response. The Biot-Gassmann model was used to convert the simulated saturation and densities to seismic velocities and synthetic seismic responses before and after injection were compared. The results show that the amplitude changes in the seismic response are detectable even for small amounts of injected CO2, while noticeable signs of velocity pushdown, as a signature of the CO2 substitution, could only be observed if the injection rate is high enough.
|
|
| 33. |
- Juhlin, Christopher, et al.
(författare)
-
Innovative Exploration Drilling and Data Acquisition Test Center: First Geophysical Site Survey
- 2019
-
Konferensbidrag (refereegranskat)abstract
- Innovative Exploration Drilling and Data Acquisition (I-EDDA) was a Network of Infrastructure in the European Institute of Innovation & Technology (EIT) Knowledge and Innovation Community (KIC) "Raw Materials", running from 2016 to 2018. Its purpose was to unite partners from academia and industry to jointly address challenges that are expected to increase the value of mineral exploration related operations. The I-EDDA test center (I-EDDA-TC) is an outcome of I-EDDA and will allow real-world test drilling to verify improved and new technologies and provide critical feedback to the engineers. Improved or newly developed technology needs to be tested under real-world conditions and in an operational setting. However, a dedicated and well-characterised test site for diamond core-drilling from the surface and with realistic conditions is missing. I-EDDA-TC will include excellent access to infrastructure, workshop facilities and proximity to expertise in drilling. The planned test site location in Örebro (south-central Sweden) is easily accessible and is situated in Paleoproterozoic bedrock (gneisses and metasediments), similar to the bedrock of many mining districts that are located in crystalline rock. The test site is planned to cover an area of approximately 4000 m2. Characterisation of the physical and chemical parameters in the subsurface performed within I-EDDA-TC will allow for an integrated interpretation of technical and geoscientific test results. Geophysical investigations will be combined with a suite of fully-cored exploration boreholes of varying depth (some down to at least 1 km), as well as downhole and laboratory investigations. A long-term utilization of the test facility will be the ultimate goal, including an invitation to the research community and to companies to partake. In July 2019 the first geophysical surveys over the site were preformed, consisting of ground magnetics, geo-electrics, a small high resolution 3D seismic survey and a deeper 2D survey using a large vibrator source. The acquired data will form the basis for future geophysical and geochemical surveys and, ultimately, for planning test boreholes for advancing drilling methods and downhole measurements. We report here on first results from these measurements.
|
|
| 34. |
- Juhlin, Christopher, 1956-, et al.
(författare)
-
Seismic and Electrical Resistivity Tomography 3D Monitoring at the Ketzin Pilot Storage Site in Germany
- 2019
-
Ingår i: Geophysics and Geosequestration. - : Cambridge University Press. - 9781316480724
-
Bokkapitel (refereegranskat)abstract
- Geosequestration involves the deep geological storage of carbon dioxide from major industrial sources, providing a potential solution for reducing the rate of increase of atmospheric concentrations of carbon dioxide and mitigating climate change. This volume provides an overview of the major geophysical techniques and analysis methods for monitoring the movement and predictability of carbon dioxide plumes underground. Comprising chapters from eminent researchers, the book is illustrated with practical examples and case studies of active projects and government initiatives, and discusses their successes and remaining challenges. A key case study from Norway demonstrates how governments and other stake-holders could estimate storage capacity and design storage projects that meet the requirements of regulatory authorities. Presenting reasons for embracing geosequestration, technical best practice for carbon management, and outlooks for the future, this volume provides a key reference for academic researchers, industry practitioners and graduate students looking to gain insight into subsurface carbon management.
|
|
| 35. |
- Kruachanta, Mingkhwan, et al.
(författare)
-
Estimation of Anisotropy Parameters, delta and epsilon : An Application to Borehole and Seismic Data from Ketzin, Germany
- 2016
-
Ingår i: CHIANG MAI JOURNAL OF SCIENCE. - : CHIANG MAI UNIV. - 0125-2526. ; 43:6, s. 1299-1305
-
Tidskriftsartikel (refereegranskat)abstract
- Weak anisotropy was indicated in a previous investigation of the 3D baseline seismic data acquired through the EU funded CO2 SINK project at the Ketzin pilot site for CO2 storage, Germany. Fourth order velocity analysis yielded the Alkhalifah anellipticity factor, or eta (eta), ranging from -0.2399 to 0.1341 for the whole study area. Although application of the simple eta term in the moveout correction allowed reflections to be flattened at far offsets, resulting in an improved seismic stacked section, the Thomsen parameters, delta (delta) and epsilon (epsilon) are of greater interest from a rock physics perspective. Borehole data from Ketzin were introduced to estimate delta and epsilon using known relationships between sonic wave velocity, NMO velocity, eta,delta and epsilon. In this paper, delta and epsilon estimations were performed using data from three wells; the CO2 injection well and two observation wells. Preliminary estimates of the Thomsen parameters give delta ranging from -0.2658 to -0.1270, while epsilon ranges from -0.2611 to -0.1141. These delta and epsilon values also indicate the presence of weak vertical transverse isotropy at the site, which is consistent with the previous study.
|
|
| 36. |
- Kruachanta, Mingkhwan, et al.
(författare)
-
Investigation of the Presence of Transverse Isotropy in the 3D Baseline Seismic Data from Ketzin, Germany
- 2015
-
Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102.
-
Konferensbidrag (refereegranskat)abstract
- In this study, we investigated the presence of transverse isotropy at the Ketzin CO2 pilot storage site, Germany. The anisotropy parameter, eta (eta), is used as an indicator of anisotropy. Preliminary results show that eta ranges from-0.2399 to 0.1341, which indicates weak anisotropy. Introducing u into the velocity estimation and applying the nonhyperbolic moveout correction resulted in an improvement in the continuity of reflections in the shallow part of the final migrated seismic data.
|
|
| 37. |
- Lueth, Stefan, et al.
(författare)
-
4D Seismic Monitoring of CO2 Storage During Injection and Post-closure at the Ketzin Pilot Site
- 2017
-
Ingår i: Energy Procedia. - : Elsevier. - 1876-6102. ; 114, s. 5761-5767
-
Tidskriftsartikel (refereegranskat)abstract
- At the Ketzin pilot site for geological CO2 storage, about 67,000 tons of CO2 were injected during the period June 2008 – August 2013. Since August 2013, the site is in its post-closure phase. Before and during the injection phase, a comprehensive monitoring programme was established. In the early post-injection phase, a majority of the monitoring activities have continued. The stepwise abandonment of the pilot site, which is planned to be accomplished in 2018, marks also the termination of most monitoring activities. Four 3D seismic surveys were acquired between 2005 and 2015 for characterizing the reservoir structure and its overburden and for monitoring the propagation of the injected CO2 in the storage formation. The first and second repeat surveys revealed the lateral extension of the CO2 plume after injecting 22 and 61 ktons, respectively. In autumn 2015, the third 3D repeat seismic survey, serving as the first post-injection survey, was acquired. The survey was acquired using the same acquisition geometry as for previous surveys, consisting of 33 templates with five receiver lines and twelve source profiles perpendicular to the receiver lines. Seismic processing of the recently acquired data has resulted in preliminary observations which can be summarized as follows: As in previous seismic repeat surveys, a clear CO2 signature is observed at the top of the storage formation. No systematic amplitude changes are observed above the reservoir which might indicate leakage. Compared to the second repeat survey acquired in 2012, the lateral extent of the CO2 plume seems to have been reduced, which may be an indication for ongoing (and relatively fast) dissolution of the CO2 in the formation brine and diffusion into very thin layers indicating pressure release.
|
|
| 38. |
- Lüth, Stefan, et al.
(författare)
-
4D Seismic Monitoring at the Ketzin Pilot Site during Five Years of Storage – Results and Quantitative Assessment
- 2015
-
Konferensbidrag (refereegranskat)abstract
- The 3D seismic and surface-downhole time-lapse monitoring at the Ketzin pilot site for CO, storage has provided the data base for a quantitative estimation of the amount of CO2 detected by the seismic surveys and of the CO2 plume thickness. The monitoring results have been compared to reservoir simulations, considering noise and thickness threshold values and indicating that conformity between monitoring and simulation results can be achieved when a thickness detection threshold of between 1 and 7 m is taken into account.
|
|
| 39. |
|
|
| 40. |
- Roberts, Roland, et al.
(författare)
-
Deep Seismic Sounding Data
- 2017
-
Rapport (populärvet., debatt m.m.)abstract
- This document is an interim report within a work package of the SERA project. The document lists a considerable number of previous Deep Seismic Sounding (DSS) projects, where data is available in some form. DSS projects are large scale, logistically complex, and there can be some problems in obtaining formal permission to use the very large seismic sources which may be necessary to be able to successfully record seismic signals penetrating to the relevant depths and distances. This implies that in some cases it would be very difficult to repeat the projects, or conduct a similar project along the same recording profile. This means that even older data can be potentially very valuable, and not all such data is available in modern, digital form (e.g. time series), and some metadata descriptions may be complicated or incomplete.In the text below, we discuss what is meant by DSS data; some of the complications related to this type of data, metadata, different forms of data, and some common types of derived (processed data) which exist. We also present information on a considerable number of DSS projects related to the European area, and list some (but far from all) relevant publications. Note that the term “database” is used in AERA. For DSS data, much data is available in well-structured and maintained digital databases, some is available in digital form only as images of seismic sections, and some data exists only in analogue form e.g. as plotted seismic sections. We consider all such types of data to be relevant, and include them in the “database” concept, as discussed below.
|
|
| 41. |
|
|
| 42. |
- Sopher, Daniel, et al.
(författare)
-
A comparison of small, affordable seismic sources at the Ketzin CO2 storage site, Germany
- 2014
-
Konferensbidrag (refereegranskat)abstract
- Seismic methods have proven to be effective for monitoring the movement and location of injected CO2 within deep saline aquifers. However, a disadvantage of seismic monitoring is the high costs associated with many repeat seismic surveys as part of a long term monitoring strategy of a CO2 storage site. As the cost for the use of the seismic source is often a significant part of the overall survey cost, affordable, smaller sources would increase the potential feasibility of a long term seismic monitoring strategy. A comparison of three land seismic sources is performed at the Ketzin CO2 storage site, Germany. Two of these sources (Vibsist 500 and Bobcat drop hammer) can be considered to be smaller and more affordable sources than those conventionally used in the seismic monitor surveys at Ketzin. In this study these smaller sources are compared to a larger more conventional Vibsist 3000 source. The subsurface target for the three sources in this comparison is the CO2 storage reservoir for the Ketzin site, located within the Triassic Stuttgart formation, which lies at a depth of approximately 600m/500ms. Two of the sources are Swept Impact (SIST) type courses (Vibsist 500 and 3000) which use hydraulic concrete breaking hammers. The third source uses a concrete breaking drop hammer tool mounted on a Bobcat loader. Data were collected along a 984m long profile with 24m receiver spacing and 12m shot spacing in 2011, 2012 and 2013 using the three different sources. A quantitative and qualitative comparison of the raw data from the three sources was performed in order to assess their relative performance. Frequency content, signal to noise ratio and penetration depth curves were calculated for the raw data. Data from the three sources was also processed using a conventional workflow to produce stacked sections which were compared. Based on the results from this study the Bobcat drop hammer source appears to perform better than the Vibsist 500 source. However both of the smaller sources were capable of producing good images of the target CO2 storage reservoir. Hence, both provide viable options as small affordable seismic sources for long term monitoring at the Ketzin site, or other shallow CO2 storage sites.
|
|
| 43. |
- Sopher, Daniel, et al.
(författare)
-
Quantitative assessment of seismic source performance : Feasibility of small and affordable seismic sources for long term monitoring at the Ketzin CO2 storage site, Germany
- 2014
-
Ingår i: Journal of Applied Geophysics. - 0926-9851 .- 1879-1859. ; 107, s. 171-186
-
Tidskriftsartikel (refereegranskat)abstract
- We apply a range of quantitative pre-stack analysis techniques to assess the feasibility of using smaller and cheaper seismic sources, than those currently used at the Ketzin CO2 storage site. Results from two smaller land sources are presented alongside those from a larger, more powerful source, typically utilized for seismic acquisition at the Ketzin. The geological target for the study is the Triassic Stuttgart Formation which contains a saline aquifer currently used for CO2 storage. The reservoir lies at a depth of approximately 630 m, equivalent to a travel time of 500 ms along the study profile. The three sources discussed in the study are the Vibsist 3000, Vibsist 500 (using industrial hydraulic driven concrete breaking hammers) and a drop hammer source. Data were collected for the comparison using the three sources in 2011, 2012 and 2013 along a 984 m long line with 24m receiver spacing and 12 m shot spacing. Initially a quantitative analysis is performed of the noise levels between the 3 surveys. The raw shot gathers are then analyzed quantitatively to investigate the relative energy output, signal to noise ratio, penetration depth, repeatability and frequency content for the different sources. The performance of the sources is also assessed based on stacked seismic sections. Based on the results from this study it appears that both of the smaller sources are capable of producing good images of the target reservoir and can both be considered suitable as lower cost, less invasive sources for use at the Ketzin site or other shallow CO2 storage projects. Finally, the results from the various pre-stack analysis techniques are discussed in terms of how representative they are of the final stacked sections.
|
|
| 44. |
- Wilczynski, Zbigniew, et al.
(författare)
-
Drill‐bit position monitoring using seismic‐while‐drilling data; numerical and field examples from Sweden
- 2023
-
Ingår i: Geophysical Prospecting. - : John Wiley & Sons. - 0016-8025 .- 1365-2478.
-
Tidskriftsartikel (refereegranskat)abstract
- The undesired drill-bit deviation is a source of drilling risks and requires monitoring. Seismic-while-drilling is one potential method to achieve this and has been tested in a number of previous studies. In August 2020 in Örebro, Sweden, we conducted an experiment to test the feasibility of seismic-while-drilling drill-bit positioning and other applications of the method. We used the hammer drill-bit signal generated while drilling a 200 m deep well in hardrock conditions and implemented vertical stacking of the subsequent impulsive signals from the hammer source, generating enhanced direct arrivals from the drill-bit. Then, we used the relative arrival times to estimate the drill-bit position for selected bit depths, confirming our methodology with two numerical studies. We successfully estimated the position of the drill-bit for the numerical examples and for several of the real data examples, with the accuracy dependent on the receiver array geometry and the quality of the data. We conclude that this drill-bit positioning method shows potential for near-real-time monitoring in drilling operations that could be applicable for both impulsive and noise-retrieved drill-bit signals.
|
|
| 45. |
- Wilczynski, Zbigniew, et al.
(författare)
-
Feasibility Study on Seismic-While-Drilling Drill Bit Deviation Monitoring
- 2022
-
Ingår i: NSG2022 28th European Meeting of Environmental and Engineering Geophysics. - : European Association of Geoscientists and Engineers.
-
Konferensbidrag (refereegranskat)abstract
- Deviation from the desired drilling trajectory may cause operational problems, which may be mitigated with a real-time monitoring of the drill bit position. In this study we examine the feasibility of using the Seismic-While-Drilling (SWD) method for monitoring the deviation of the drill bit based on a case study using the continuous seismic records of a 200 m hammer drilling operation in a hard rock environment in Örebro, Sweden. As a seismic source, we consider the subsequent hammer hits. We propose a processing sequence to retrieve the seismic arrivals from a certain depth. Then, we use the traveltimes to locate the source (drill-bit) position. The results show that the method has the potential to monitor the deviation of the drill bit in near-real-time.
|
|
| 46. |
|
|
| 47. |
|
|
| 48. |
- Zhang, Fengjiao, 1981-, et al.
(författare)
-
Application of seismic waveform tomography to monitoring of CO2 injection : modeling and a real data example from the Ketzin site, Germany
- 2013
-
Ingår i: Geophysical Prospecting. - : Wiley-Blackwell. - 0016-8025 .- 1365-2478. ; 61:Suppl.s1, s. 284-299
-
Tidskriftsartikel (refereegranskat)abstract
- Seismic monitoring of the injected carbon dioxide (CO2) distribution at depth is an important issue in the geological storage of CO2. To help monitor changes in the subsurface during CO2 injection a series of 2D seismic surveys were acquired within the framework of the CO2SINK and CO2MAN projects at Ketzin, Germany at different stages of the injection process. Here we investigate using seismic waveform tomography as a qualitative tool for time-lapse seismic monitoring given the constraints of the limited maximum offsets of the 2D seismic data. Prior to applying the inversion to the real data we first made a number of benchmark tests on synthetic data using a similar geometry as in the real data. Results from the synthetic benchmark tests show that it is difficult to recover the true value of the velocity anomaly due to the injection, but that it is possible to qualitatively locate the distribution of the injected CO2. After the synthetic studies, we applied seismic waveform tomography on the real time-lapse data from the Ketzin site along with conventional time-lapse processing. Both methods show a similar qualitative distribution of the injected CO2 and agree well with expectations based upon more extensive 3D time-lapse monitoring in the area.
|
|
| 49. |
|
|
| 50. |
- Zhang, Fengjiao, et al.
(författare)
-
Passive seismic interferometry imaging : An example from the Ketzin pilot CO2 geological storage site
- 2022
-
Ingår i: Journal of Applied Geophysics. - : Elsevier. - 0926-9851 .- 1879-1859. ; 205
-
Tidskriftsartikel (refereegranskat)abstract
- Ketzin is a well-known onshore CO2 geological storage test site. Injection started in June 2008 and ended in August 2013. About 67 kt of CO2 was injected into a saline aquifer reservoir. Numerous geophysical surveys have been conducted at the site, including passive seismic ones. Passive seismic interferometry can be applied in many seismic exploration investigations to image the underground structures. This study compares several passive seismic interferometry imaging methods to a data set acquired at Ketzin. The passive data set consist of 5 lines with 20 h of recordings in total. First, we apply the autocorrelation method to obtain zero offset stacked sections directly. Secondly, we test different interferometry methods to generate virtual shot gathers. These virtual shot gathers are then processed to obtain CDP stacked sections. Results from these methods are compared with an active data set recorded at the site. The processed passive sections have relatively less coherent reflections compared with the active stacked sections. However, the passive sections obtained by autocorrelation show good agreement with the active stacked sections. The stacked sections obtained by processing virtual shot gathers using crosscorrelation show similar features to the active stacked sections, but with poorer coherence in the reflections and are noisier than the autocorrelation sections.
|
|
